CBSE
Multiple Choice QuestionsAcceleration due to gravity at earth's surface is 'g'ms-2 . Find the effective value of gravity at a height of 32 km from sea level (Re=6400km)
0.5 gms-2
0.99 gms-2
1.01 gms-2
0.90 gms-2
The earth of mass =6×1024 kg revolves around the sun with an angular velocity of 2×10-7 rad/s in a circular orbit of radius 1.5×108 km. The force exerted by the sun on earth is
6×1019 N
18×1025 N
36×1021 N
27×1039 N
Two planets are revolving around the earth with velocities v1 and v2 and in radii r1 and r2 ( r1 > r2 ) respectively. Then :
v1 = v2
v1 > v2
v1 < v2
Radius of orbit of satellite of earth is R. Its kinetic energy is proportional to
R
The dimensions of gravitational constant are
Near earth's surface, time period of a satelliteis 4 hrs. Find its time period at height '4R' from the centre of earth
32 hrs
8hrs
16hrs
A ball is thrown from height 'h' and another from '2h'. The ratio of time taken by the two balls to reach ground is
2:1
1:2
Dimension of relative density is
kgm-3
ML-3
dimensionless
M2L-6
A ball is thrown upwards, it takes 4sec to reach back to the ground. Find its initial velocity
30ms-1
10ms-1
40ms-1
20ms-1
The ratio of electrostatic and gravitational forces acting between electron and proton separated by a distance 5×1011m will be (charge on electron =1.6×10-19 C, mass of electron =9.1×10-31 kg, mass of proton =1.6×10-27 kg, G=6.7×10-11 Nm2/kg2 )
2.36×1039
2.36×1040
2.36×1041
2.34×1042
